Asphalt pavement construction



y 22, 1956 1. L. EDGERTON 2,746,733

ASPHALT PAVEMENT CONSTRUCTION Filed Dec. 9, 1953 ATTO'RNEY United StatesPatent "Oifice 2,746,733 Patented May 22, 1956 2,746,733 ASPHALTPAVEMENT eoNsrnuc'rlo Ira L. Edgerton, Edgewood, R. I. ApplicationDecember 9,1953, Serial No. 397,100

7 Claims. Cl. 259-147 An additional object of the invention is toutilize steam 1 pressure for quickly elevating sand andgravel to amixing chamber While simultaneously imparting ,heat thereto.

With the above and other objects and advantageous features in view, theinvention consists of a novel method and apparatus more fully disclosedin the detailed description following, in conjunction with theaccompanying drawings, and more specifically defined in the claimsappended thereto.

In the drawings,

Fig. l is a diagrammatic view of one embodiment of my invention;

Fig. 2 is a bottom plan view of the disperser of Fig. 1 on the line 2-2thereof; and

Fig. 3 is a view of the asphalt jet positions on line 3--3 of Fig. 1.

It has been found advantageous to provide an arrangement by which sandand gravel fed into a hopper at ground level are elevated to a higherlevel by means of steam pressure, the steam heating the sand and gravelduring the elevation to a high temperature, whereby the heated sand andgravel may then be gravity fed into a mixing chamber into which liquidasphalt is injected to be thoroughly mixed with the sand and gravel in acyclonic whirl produced by a further injection of directed high pressuresteam. To this end, I arrange a series of hoppers at difierent levelsfrom the ground connected by pipes provided with injection nozzles forsteam, and I initially place a load of sand and gravel in the lowerlevel hopper. Steam is injected at both high and low pressure, the lowpressure steam being for the purpose of heating the sand and gravel andthe high pressure steam being periodically injected to propel andelevate the heated sand and gravel through the pipes and into thehoppers, the highest level hopper functioning as a supply bin from whichthe heated sand and gravel falls down by gravity into a mixing chamber,where it is dispersed and whirled around by a directed stream of highpressure steam and thoroughly mixed with asphalt liquid injected intothe mixing chamber, whereby a mixed asphalt product of high quality isobtained.

Referring to the drawings, Fig. 1 illustrates a preferred arrangement ofapparatus for carrying out the process, consisting of a lower hopper bin10, an intermediate hopper bin 11 positioned at a higher level andconnected to the lower hopper bin 10 by a conduit 12, and an upperhopper bin 13 positioned at a suitable level above the intermediate 2hopper bin 11, to which it is connected by a conduit 14 and which is setto discharge into a mixing chamber 15.

The lower hopper bin 10 is cone shaped at its lower end, as illustrated,and is provided with heating jets 16, 17 lead ing thereinto and carryingheating steam from a source, not shown, for heating the sand and gravelwithin the bin, and a syphon jet 18 carrying steam under high pressurepositioned at the lower section of the bin and directed upwardly intothe conduit 12, whereby steam at high pressure will propel the sand andgravel upwardly through the tubing 12 and into the intermediate hopperbin 11, the waste steam escaping through a vent 19.

The intermediate hopper bin 11 also is cone shaped at its lower end andhas steam heating jets 20, 21 for injecting steam into the bin to keepthe sand and gravel hot and a second siphon jet 22 carrying highpressure steam for propelling the sand and gravel, while keeping it hotthrough the conduit 14 and upwardly into the upper hopper bin 13, thewaste steam escaping through a vent 23.

The upper hopper 13 has two heating jets 24, 25 for pouring steam intothe sand and gravel to maintain the sand and gravel hot, and has a coneshaped lower portion with a trap door 26 which is operatively opened bya control.27, whereby the hot sand and gravel are allowed to pass intothe mixing chamber 15 over a disperser 28 which is conical in shape andhas its base 29 formed with arcuate shaped guide surfaces 30, see Fig.2.

The mixing chamber includes a funnel 31 centrally positioned under thedisperser 28, a V-shaped floor 32 with a central opening 33 having atrap door 34 operatively opened by a control 35 for passage of thecontents from the mixing chamber, asphalt jets 36 tangentiallypositioned as illustrated in Fig. 3 for injecting hot liquid asphaltinto the chamber in a circular spray, a steam jet 37 for shooting steamunder high pressure up through the funnel 30, and a vent chamber 38leading to atmosphere and concentric with the upper bin 13.

The operation of my invention may now be explained. Sand and gravel arefed into the lower bin and heated by steam from the heating jets.Periodically, after a substantial amount of heat has thus been added,steam under high pressure is injected through the siphon jet to forcethe sand and gravel up through the conduit into the intermediate bin,where the procedure is repeated and hot sand and gravel are elevated tothe upper bin. Heat is again applied to the sand and gravel in the highbin, the heated sand and gravel being periodically allowed to flowthrough the trap door by gravity into the disperser in the mixingchamber. As the hot sand and gravel fall into the mixing chamber, acontinuous blast of steam under high pressure is forced through themixing chamber funnel and against the base of the conical disperser toset up a cyclonic whirl within the mixing chamber and thus to churn upthe hot sand and gravel with hot liquid asphalt, which is injected intothe mixing chamber at an angle to intensify the whirling movement of themixture within the mixing chamber. The sand and gravel are thusthoroughly mixed and coated with asphalt, whereby a high quality mixsuitable for pavements is provided, the mix being poured through themixing chamber trap door and into a conveyer receptacle as desired.

My invention thus includes a novel method and a novel arrangement forpreparing an asphalt mix suitable for pavements and the like, which hasno moving mechanical parts, is simple and economical in operation, andprovides a uniform product of high quality.

Although I have described a specific embodiment of my invention, it isobvious that changes in the size, shape and arrangement of the parts maybe made to meet other mix requirements without departing from the spiritand the scope of the invention as defined in the appended claims.

My invention has the advantage that dust and the like becomes entrainedin the heating steam and is conveyed through the apparatus into thefinal mix, without spreading through the air and creating a neighborhooddust problem. Y

I claim:

1. The method of manufacturing an asphalt mix comprising the steps ofheating a mixture of sand and gravel, elevating the heating mixture to astorage chamber, periodically releasing heated mixture from the storagechamber, dispersing the released heating mixture and conducting thedispersed mixture into a mixing chamber, and whirling the dispersedmixture in the mixing chamber while simultaneously injecting liquidasphalt into the whirling dispersed mixture, whereby a thoroughlydispersed sand, gravel and asphalt mixture for pavements is formed.

2. The method of claim 1, including the step of heating the sand andgravel mixture with steam.

3. The method of claim 2, including the step of elevating the heatedsand and gravel mixture with high pressure steam.

4. The method of claim 3, including the step of whirling the sand andgravel mixture with steam.

5. An apparatus for manufacturing an asphalt mix for pavementsconsisting of means for heating sand and gravel, means for elevating theheated sand and gravel, means for periodically dispersing the elevatedheated sand and gravel, a mixing chamber, means for passing thedispersed sand and gravel into the mixing chamber, means for whirlingthe dispersed sand and gravel within said mixing chamher, and means forsimultaneously injecting liquid asphalt into the whirling sand andgravel, whereby an asphalt mix for pavements is formed.

6. An apparatus for manufacturing an asphalt mix for pavementsconsisting of means for heating sand and gravel, means for propellingand elevating the heated sand and gravel by high pressure steam, meansfor periodically dispersing the elevated heated sand and gravel, amixing chamber, means for passing the dispersed sand and gravel into themixing chamber, means for whirling the dispersed sand and gravel withinsaid mixing chamber, and means for simultaneously injecting liquidasphalt into the whirling sand and gravel, whereby an asphalt mix forpavements is formed.

7. An apparatus for manufacturing an asphalt mix for pavementsconsisting of means for heating sand and gravel, means for elevating theheated sand and gravel, means for periodically dispersing the elevatedheated sand and gravel, a mixing chamber, means for passing thedispersed sand and gravel into the mixing chamber, means including highpressure steam for whirling the dispersed sand and gravel within saidmixing chamber, and means for simultaneously injecting liquid asphaltinto the whirling sand and gravel, whereby an asphalt mix for pavementsis formed.

References Cited in the file of this patent UNITED STATES PATENTS808,599 Crichfield Dec. 26, 1905 1,920,463 Edwards Aug. 1, 19332,005,800 OBoyle June 25, 1935 2,028,745 Hendrick et al Jan. 28, 1936FOREIGN PATENTS 102,185 Switzerland Nov. 16, 1923 385,212 Germany Dec.3, 1923

